Özet:

The relationship between interest rates and inflation rates is often addressed in the framework of Fisher hypothesis. According to Fisher’s hypothesis, changes in inflation rates affect the nominal interest rate in the same direction. Thus, the real interest rate is not affected by the inflation rate and shows a release around a certain average in the long term. Therefore, in a country where the Fisher hypothesis applies, there is a long-term relationship between the nominal interest rates and inflation rates and the real interest rate is expected to be stable. In this study, the validity of the Fisher hypothesis in the period 1988:10-2019:01 in Turkey was studied by the Fourier approach. In this framework, the Fourier unit root test was applied to the nominal interest rates and inflation rates, and the variables were found to be unitary and stable when the first difference was taken. The Fourier equalization test was subsequently implemented in order to test the existence of the long-term relationship between the variables, and the one-way long-term relationship was found from the inflation rate to the nominal interest rate. Finally, the stagnation of the real interest rate was again studied by the Fourier unit root test and found that it was stagnant at the level. This situation supports the findings obtained from the matching test. The findings prove that the Fisher hypothesis is valid in Turkey.